Radioimmunoassay techniques are to be used to measure plasma arginine - vasopressin levels in humans under a variety of conditions. Investigations will include the effects of diabetic hyperosmolar coma, cirrhosis and congestive failure, menstrual cycle and anoxia. The metabolism, distribution and plasma protein binding of vasopressin will be studied by radioimmunoassay. In addition, the distribution and binding of radioactively labeled and unlabeled vasopressin will be studied in animals.